September 25, 2020
In the early 1960s, laser cutting technology advanced so fast that figuring out how it could be put to work took a while. It was only a matter of time before it caught the attention of the world at large and industry in particular. Laser cutting has the advantages of speed, precision, efficiency, economy, and adaptability, all with a remarkably small kerf. Despite the advances in technology, there hasn’t been much of a challenge to laser to date. Laser cutting gives a higher quality cut compared to competing processes such as punchcutting, plasma cutting, abrasive waterjet cutting, ultrasonic cutting, oxyfuel cutting, sawing, and milling.
The major difference between CO2 and fiber lasers lies in the way the beam is generated and guided. But when it comes to the cutting head, the operation is the same. Here with the help of lenses, the laser beam is focused on a specific area of the surface, which melts as a result of the rapid increase in temperature.
At the same time, the area is blasted with an assist gas that is supplied through a gas connection. The quality of the cut is affected by many factors, including the following:
The assist gas used also plays a significant role in the cut quality. The gas used can influence the required cutting power, fogging of lenses/mirrors by fumes, area affected by heat, cut zone, and effectiveness in removing molten material. Of course, the benefits are only secured when the assist gas is used at the right flow rate, pressure, purity and quantity.
Nitrogen, oxygen and air are the most common assist gases used in the laser cutting of metal. While the choice of gas depends on the purpose, nitrogen is by far the most popular for cutting metal when a high-quality cutting edge is required. Oxygen is highly reactive, so the cutting edge created with it is not as fine as that of nitrogen; however, as it boosts the power of the laser beam, it cuts fast and deep and is preferred for cutting through thicker metals. Similarly, air too does not create a fine cutting edge, but it is less costly and is preferred for cutting where the metal will undergo further processing.